body {
  margin: 0;
  font-family: Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  transition: 0.4s;
}

header {
  padding: 20px;
  text-align: center;
}

#logo {
  width: 90px;
  height: 90px;
  margin: auto;
  background-size: cover;
  animation: zap 1.3s infinite alternate;
}

@keyframes zap {
  from { filter: brightness(0.8); }
  to   { filter: brightness(1.4); }
}

nav {
  text-align: center;
  margin-bottom: 20px;
}

nav a {
  margin: 0 12px;
  text-decoration: none;
  font-size: 18px;
  color: var(--accent);
}

textarea {
  width: 100%;
  height: 120px;
  padding: 10px;
  margin-bottom: 10px;
}

button {
  padding: 10px 14px;
  margin-top: 5px;
  cursor: pointer;
}

/* THEMES ----------------------------------*/

:root {
  --bg: #0d0d0d;
  --text: #ffffff;
  --accent: #2b82ff;
  --logo: url('batman.png');
}

.flash-mode {
  --bg: #ffefc0;
  --text: #550000;
  --accent: #ff2b2b;
  --logo: url('flash.png');
}

#logo {
  background-image: var(--logo);
}

.entry {
  padding: 10px;
  margin-bottom: 8px;
  border-bottom: 1px solid var(--accent);
}